macOS watchdog: detect deck via ioreg sessionID

system_profiler SPUSBDataType was silently omitting the deck on some Macs
(watchdog exited early, never restarted anything) and, when it did report,
the trailing bus number in "Location ID: X / N" flapped without an actual
replug — causing spurious restarts. ioreg sees the device reliably and
sessionID changes only on real re-enumeration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

systemd/streamdeck-go-watchdog.sh

@@ -51,20 +51,23 @@ current_addr() {
             '
             ;;
         Darwin)
-            # system_profiler entry per device:
-            #     Stream Deck XL:
-            #       Product ID: 0x00ba
-            #       Vendor ID: 0x0fd9 (Elgato ...)
-            #       ...
-            #       Location ID: 0x14140000 / 5
-            # The trailing "/ N" is the bus address — it changes on replug.
-            system_profiler SPUSBDataType 2>/dev/null | awk -v pids="$PIDS_RE" '
-                /^[[:space:]]*Product ID:/  { pid = $3 }
-                /^[[:space:]]*Vendor ID:/   { vid = $3 }
-                /^[[:space:]]*Location ID:/ {
-                    sub(/^[[:space:]]*Location ID:[[:space:]]*/, "")
-                    if (vid == "0x0fd9" && pid ~ ("^0x(" pids ")$")) {
-                        print
+            # ioreg is the reliable source on macOS — system_profiler SPUSBDataType
+            # silently omits the deck on some machines, and its "Location ID: X / N"
+            # trailing bus number flaps spuriously without an actual replug.
+            #
+            # sessionID is unique per USB enumeration session: stable while the
+            # device stays plugged in, changes on every replug. Exactly what we want.
+            #
+            # Elgato vendor in decimal: 4057 (0x0fd9).
+            # Stream Deck product IDs in decimal: 186 (0x00ba), 108 (0x006c), 109 (0x006d).
+            ioreg -p IOUSB -l -w 0 2>/dev/null | awk '
+                /<class IOUSBHostDevice/ { vid=""; pid=""; sid="" }
+                /"idVendor"/    { vid=$NF }
+                /"idProduct"/   { pid=$NF }
+                /"sessionID"/   { sid=$NF }
+                /}/ {
+                    if (vid == "4057" && (pid == "186" || pid == "108" || pid == "109") && sid != "") {
+                        print sid
                         exit
                     }
                 }